In the "unintended consequences" category, I've noticed that since the introduction of the Epic/Legendary badge, I now avoid downvoting unless one of the following is true:

I am at less than 200 points for the day, and it's close to 00:00 UTC so I'm unlikely to actually reach the rep cap, or

I am already past the 200 points per day due to an accepted answer or bounty accept after reaching 200 points

That is, if I'm at exactly 200 points for the day then I will refrain from downvoting because doing so would put me below the 200 points required for one more day toward Epic/Legendary. 199 points in a day doesn't count.